Liquid crystal display device

ABSTRACT

A liquid crystal display device includes a first substrate. A second substrate is facing the first substrate. A liquid crystal layer is interposed between the first and second substrates. At least one pixel area is defined by a plurality of gate lines and a plurality of drain lines arranged in a matrix over the first substrate, wherein the plurality of gate lines are extending in a first direction, and the plurality of drain lines are extending in a second direction. A first electrode is assigned to the pixel area, wherein the first electrode is provided over the first substrate. A second electrode is assigned to the pixel area and is facing the first electrode, wherein the second electrode is provided over the first substrate and is transparent. The second electrode has a solid portion and a hollow portion. The hollow portion is superposed to at least a portion of the first electrode. An insulating layer is provided between the first and second electrodes.

CROSS-REFERENCES TO RELATED APPLICATIONS

[0001] The present application is related to and claims priority fromJapanese Patent Application No. 2000-003348, filed Jan. 12, 2000.

BACKGROUND OF THE INVENTION

[0002] The present invention relates to a liquid crystal display deviceand, more particularly, to a liquid crystal display device which iscalled In-Plane Switching Mode.

[0003] Liquid crystal display device which is called In-Plane SwitchingMode has a construction in which a pixel electrode and a counterelectrode which causes an electric field (an in-plane electric field)having a component parallel to transparent substrates to be generatedbetween the counter electrode and the pixel electrode are formed in eachliquid crystal-side pixel area of one of the transparent substratesdisposed in opposition to each other with a liquid crystal interposedtherebetween.

[0004] This type of liquid crystal display device is constructed so thatthe amount of light to be transmitted through the area between the pixelelectrode and the counter electrode is controlled by the driving of theliquid crystal to which the electric field is applied.

[0005] Such a liquid crystal display device is known as a type which issuperior in so-called viewing angle characteristics and enables adisplayed image to be unchanged even when its display surface isobserved from an oblique direction.

[0006] The pixel electrode and the counter electrode have so far beenformed of a metal layer which does not transmit light therethrough.

[0007] In recent years, a liquid crystal display device constructed inthe following manner has been known: a counter electrode made of atransparent electrode is formed over the entire area of a pixel areaexcept the periphery thereof, and strip-shaped pixel electrodes areformed on the counter electrode with an insulating film interposedtherebetween, in such a manner as to be extended in one direction and tobe juxtaposed in a direction traverse to the one direction.

[0008] The liquid crystal display device having this construction causesan in-plane electric field to be generated between each of the pixelelectrodes and the counter electrode, and is still superior in viewingangle characteristics and is greatly improved in aperture ratio.

[0009] Incidentally, this art is described, for example, in SID (Societyfor Information Display) 99 DIGEST: pp. 202-205 and Japanese PatentLaid-Open No. 202356/1999, which is incorporated herein by reference.

[0010] However, in the liquid crystal display device having thisconstruction, the occurrence of so-called horizontal smear is visuallyobserved on its display portion, and the occurrence of image retentionis also visually observed.

[0011] It has been found out that the cause of the occurrence ofhorizontal smear is that the capacitance between the counter electrodeformed over the entire area of the pixel area except the peripherythereof and the plural strip-shaped pixel electrodes formed injuxtaposition on the counter electrode with the insulating filminterposed therebetween becomes larger than in previous type and thecharge of the pixel electrodes with signal voltages becomesinsufficient, and also the voltage of the counter electrode is distortedand the time required for the distorted voltage to be restored to itsoriginal state becomes long.

[0012] It has also been found out that the cause of the occurrence ofimage retention is that an electric field other than an electric fieldwhich has a component parallel to the substrate between the pixelelectrode and the counter electrode and contributes to the control ofthe optical transmissivity of the liquid crystal, i.e., an electricfield having a component perpendicular to the substrate between thecounter electrode and the pixel electrode, is excessively strong.

SUMMARY OF THE INVENTION

[0013] The present invention has been made on the basis of theabove-described situations, and provides a liquid crystal display devicewhich can restrain the occurrence of horizontal smear.

[0014] The present invention also provides a liquid crystal displaydevice which can restrain the occurrence of image retention.

[0015] A representative aspect of the invention disclosed in the presentapplication will be described below in brief.

[0016] In one embodiment, a liquid crystal display device includes afirst substrate. A second substrate is facing the first substrate. Aliquid crystal layer is interposed between the first and secondsubstrates. At least one pixel area is defined by a plurality of gatelines and a plurality of drain lines arranged in a matrix over the firstsubstrate, wherein the plurality of gate lines are extending in a firstdirection, and the plurality of drain lines are extending in a seconddirection. A first electrode is assigned to the pixel area, wherein thefirst electrode is provided over the first substrate. A second electrodeis assigned to the pixel area and is facing the first electrode, whereinthe second electrode is provided over the first substrate and istransparent. The second electrode has a solid portion and a hollowportion. The hollow portion is superposed to at least a portion of thefirst electrode. An insulating layer is provided between the first andsecond electrodes.

[0017] In another embodiment, a liquid crystal display device accordingto the present invention includes a pair of substrates, a liquid crystallayer interposed between the pair of substrates, a plurality of pixelparts being constructed with a plurality of gate lines and a pluralityof drain lines arranged in a matrix on one of the pair of substrates, atleast one pair of the first electrodes and the second electrodesprovided for each pixel part between one of the pair of substrates andthe liquid crystal layer, wherein the first electrode and the secondelectrode being disposed with an insulating film interposedtherebetween, and the second electrode is transparent electrode formedin a rectangular shape and having a slit formed in a portion which issuperposed on the first electrodes.

[0018] In the liquid crystal display device constructed in this manner,the selected ones of the plural electrodes of the other electrode (forexample, pixel electrodes) are formed not to be superposed on the one ofthe pair of electrodes (for example, a counter electrode).

[0019] Accordingly, it is possible to decrease the capacitance occurringbetween the pixel electrode and the counter electrode, whereby it ispossible to restrain the occurrence of horizontal smear.

[0020] In addition, it is possible to weaken an electric field otherthan an electric field which contributes to the control of the opticaltransmissivity of the liquid crystal, i.e., an electric field having acomponent perpendicular to the substrate between the counter electrodeand the pixel electrode, from among electric fields occurring betweenthe pixel electrode and the counter electrode, whereby it is possible torestrain the occurrence of image retention.

[0021] Moreover, since the holes formed in the other-side electrode aredisposed with respect to one-side electrodes that are not adjacent toone another, the holes are formed with a comparatively large space,whereby the holes have the advantage of being easily worked.

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The present invention will be more apparent from the followingdetailed description, when taken in conjunction with the accompanyingdrawings, in which:

[0023]FIG. 1 is a plan view showing one embodiment of a pixel of aliquid crystal display device according to the present invention;

[0024]FIG. 2 is a cross-sectional view taken along line 2-2 of FIG. 1;

[0025]FIG. 3 is a cross-sectional view taken along line 3-3 of FIG. 1;

[0026]FIG. 4 is a cross-sectional view take along line 4-4 of FIG. 1;

[0027]FIG. 5 is an explanatory view showing the positional relationshipbetween pixel electrodes and holes formed in a counter electrode of theliquid crystal display device according to the present invention;

[0028]FIG. 6 is a plan view showing one embodiment of the whole of theliquid crystal display panel of the liquid crystal display deviceaccording to the present invention;

[0029]FIG. 7 is a view showing the equivalent circuit of the liquidcrystal panel according to the present invention;

[0030]FIG. 8 is a cross-sectional view showing another embodiment of theliquid crystal display device according to the present invention; and

[0031]FIG. 9 is a plan view showing another embodiment of the liquidcrystal display device according to the present invention.

DESCRIPTION OF THE SPECIFIC EMBODIMENTS

[0032] Preferred embodiments of the liquid crystal display deviceaccording to the present invention will be described below.

[0033] [Embodiment 1]

[0034] <<Construction of Pixel>>

[0035]FIG. 1 is a plan view showing the construction of a pixel area ofa liquid crystal display device (panel) according to the presentinvention as viewed from the liquid-crystal side of one of transparentsubstrates disposed in opposition to each other with a liquid crystalinterposed therebetween.

[0036]FIG. 2 is a cross-sectional view taken along line 2-2 of FIG. 1,FIG. 3 is a cross-sectional view taken along line 3-3 of FIG. 1, andFIG. 4 is a cross-sectional view take along line 4-4 of FIG. 1.

[0037] Referring first to FIG. 1, gate signal lines GL are disposed tobe extended in the x-direction of FIG. 1 and to be juxtaposed in they-direction of FIG. 1, and the gate signal lines GL are formed of, forexample, chromium (Cr). These gate signal lines GL form a rectangulararea together with drain signal lines DL which will be described below,and the area constitutes a pixel area.

[0038] A counter electrode CT which generates an electric field betweenthe counter electrode CT and pixel electrodes PX which will be describedbelow are formed in this pixel area. This counter electrode CT is formedin the central portion of the pixel area except the periphery thereof,and is made of, for example, ITO1 (Indium-Tin-Oxide) which forms atransparent conductive layer.

[0039] As will be described later in detail, the plural pixel electrodesPX are formed in juxtaposition, and the counter electrode CT is formedin such a manner as to be superposed on the plural pixel electrodes PXwith an insulating film GI interposed therebetween. Holes CTH arerespectively formed in the portions of the counter electrode CT that aresuperposed on every other one of the pixel electrodes PX. As usedherein, the term “superpose” refers a structural relationship betweentwo materials, where one material is overlapping or vertically alignedto another material in part or in whole without regards as to whichmaterial is provided on top. For example, the counter electrode CT,which has been described above as being “superposed” to the pixelelectrodes, may be provided above the pixel electrodes or beneath thepixel electrodes, according to the definition provided herein.Similarly, the term “overlap” merely refers to describe a situationwhere one material is provided over another material without making anylimitation as to which material is provided on top.

[0040] A counter voltage signal line CL is formed to be connected to thecounter electrode CT in such a manner as to border the entire peripherythereof. This counter voltage signal line CL is formed integrally withcounter voltage signal lines CL which are similarly formed at therespective counter electrodes CT in the right and left pixel areas asviewed in FIG. 1 (i.e., the corresponding one of the pixel areas arrayedalong the gate signal lines GL).

[0041] In this case, the counter voltage signal lines CL are connectedto one another at each of locations above and below the pixel areas.This construction is intended to minimize the portion of superpositionof each of the counter voltage signal lines CL and the adjacent one ofthe drain signal lines DL which will be described later, therebyreducing the capacitance generated therebetween.

[0042] Each of these counter voltage signal lines CL is formed of anopaque material made of, for example, chromium (Cr). In this case, evenif an electric field which acts as noise is generated between any of thedrain signal lines DL which will be described later and the periphery ofthe adjacent one of the counter electrodes CT and the opticaltransmissivity of the liquid crystal is not obtained as desired, thatportion is shielded by the counter voltage signal line CL, whereby it ispossible to solve a problem in terms of display quality.

[0043] This also means that it is possible to solve a problem due to anelectric field (noise) which is generated between any of the gate signallines GL and the periphery of the adjacent one of the counter electrodesCT.

[0044] In addition, as described above, since the material of thecounter voltage signal lines CL is identical to that of the gate signallines GL, the counter voltage signal lines CL and the gate signal linesGL can be formed in the same process, whereby it is possible to avoid anincrease in the number of manufacturing steps.

[0045] It goes without saying that the material of the counter voltagesignal lines CL is not limited to Cr and the counter voltage signallines CL may be formed of, for example, Al or a material which containsAl.

[0046] In this case, it is effective to position the counter voltagesignal lines CL as a layer which overlies the counter electrodes CT.This is because Al is easily melted by an etching solution (for example,HBr) for selectively etching an ITO film which constitutes the counterelectrodes CT.

[0047] Furthermore, it is effective to interpose a high melting pointmetal such as Ti, Cr, Mo, Ta or W at least the interface between each ofthe counter voltage signal lines CL and the adjacent one of the counterelectrodes CT.. This is because ITO which constitutes the counterelectrodes CT oxidizes Al of the counter voltage signal lines CL andgenerates a high-resistance layer.

[0048] For this reason, as one example, if the counter voltage signallines CL made of Al or a material which contains Al are to be formed, itis preferable to form each of the counter voltage signal lines CL as amultilayered structure having a first layer made of the high meltingpoint metal.

[0049] In this manner, the counter electrodes CT, the counter voltagesignal lines CL and the gate signal lines GL are formed over thetransparent substrate, and the insulating film GI made of, for example,SiN is formed over the transparent substrate in such a manner as tocover all of the counter electrodes CT, the counter voltage signal linesCL and the gate signal lines GL.

[0050] The insulating film GI has the function of an interlayerinsulating film for insulating the drain signal lines DL from thecounter voltage signal lines CL and the gate signal lines GL. Theinsulating film GI also has the function of a gate insulating film ineach area in which a thin film transistor TFT which will be describedbelow is formed, as well as the function of a dielectric film in eacharea in which a capacitance element Cstg which will be described belowis formed.

[0051] The thin film transistor TFT is formed to be superposed on aportion of the gate signal line GL (the bottom left portion of FIG. 1),and in this portion, a semiconductor layer AS made of, for example,amorphous silicon (a—Si) is formed on the insulating film GI.

[0052] A source electrode SD1 and a drain electrode SD2 are formed onthe upper surface of the semiconductor layer AS, whereby an invertedstaggered structure MIS transistor is formed which uses a portion of thegate signal line GL as its gate electrode. The source electrode SD1 andthe drain electrode SD2 are formed at the same time as the drain signalline DL.

[0053] Specifically, the drain signal lines DL which are disposed to beextended in the y-direction of FIG. 1 and to be juxtaposed in thex-direction of FIG. 1 are formed, and a portion of an adjacent one ofthe drain signal lines DL is extended to the surface of thesemiconductor layer AS and constitutes the drain electrode SD2 of thethin film transistor TFT.

[0054] During the formation of the adjacent drain signal line DL, thesource electrode SD1 is formed, and this source electrode SD1 isextended to the inside of the pixel area, thereby integrally forming acontact portion which provides connection between the thin filmtransistor TFT and the pixel electrode PX which will be described below.

[0055] As shown in FIG. 3, a contact layer d0 which is doped with, forexample, an n type impurity is formed at the interface between thesource electrode SD1 and the drain electrode SD2 of the semiconductorlayer AS.

[0056] This contact layer d0 is formed by forming an n typeimpurity-doped layer over the entire surface of the semiconductor layerAS, and, after forming the source electrode SD1 and the drain electrodeSD2, etching the n type impurity-doped layer on the portion of thesurface of the semiconductor layer AS that is exposed between theseelectrodes SD1 and SD2, by using each of these electrodes SD1 and SD2 asa mask.

[0057] In Embodiment 1, the semiconductor layer AS is formed not only inthe area in which the thin film transistor TFT is formed, but also atthe intersection of the drain signal line DL and the gate signal line GLand at the intersection of the drain signal line DL and the countervoltage signal line CL. This construction is intended to strengthen thefunction of the interlayer insulating film.

[0058] A protective film PSV covers the thin film transistor TFT formedover the surface of a transparent substrate SUB1 on which the thin filmtransistor TFT is formed. The protective film is generally made of adielectric material, for example, SiN. The protect film prevents thethin film transistor TFT from coming into direct contact with the liquidcrystal LC.

[0059] Furthermore, the pixel electrode PX which is made of atransparent conductive film are formed over the upper surface of theprotective film PSV . The pixel electrode PX is generally made of aconductive material, for example, Indium-Tin-Oxide (ITO2).

[0060] In Embodiment 1, five pixel electrodes PX are formed to besuperposed on an area in which the counter electrode CT is formed, andare also formed to be extended in the y direction of FIG. 1 and to beequidistantly spaced apart from one another. Both ends of each of thefive pixel electrodes PX are connected to the respective ends of theadjacent one by layers made of the same material which is formed to beextended in the x direction of FIG. 1.

[0061] In this construction, three pixel electrodes PX which arerespectively disposed at the first, third and fifth positions as viewedfrom the left side of FIG. 1 are positioned in the respective holes CTHformed in the counter electrode CT.

[0062] Specifically, within a substantial pixel area, i.e., within theaperture of a black matrix, each of the first, third and fifth pixelelectrodes PX is formed without being superposed on the counterelectrode CT, and the other pixel electrodes PX which are respectivelydisposed at the second and fourth positions as viewed from the left sideof FIG. 1 are formed to be superposed on the counter electrode CT.

[0063] In the case where the pixel electrodes PX are formed in thismanner, since the area of superposition of the pixel electrodes PX andthe counter electrodes CT can be decreased, the capacitance between thepixel electrodes PX and the counter electrodes CT can be decreased,whereby it is possible to decrease the occurrence of so-calledhorizontal smear.

[0064] In this construction, the holes CTH are formed in the counterelectrode CT in such a manner as to correspond to every other one of thepixel electrodes PX. This construction is intended to facilitate theworking of the holes CTH by increasing the spaces between the adjacentholes CTH.

[0065] In Embodiment 1, the number of pixel electrodes PX per pixel areais five, but there actually are cases in which dozens of pixelelectrodes are formed per pixel area. In such a case, the holes CTH maybe formed at positions which correspond to not only every other one ofthe pixel electrodes PX but also every third one, every fourth one andso on, whereby it is possible to achieve far easier working of the holesCTH.

[0066]FIG. 8 is a view which shows such a construction and correspondsto FIG. 2. In the construction shown in FIG. 8, the holes CTH are formedin the counter electrode CT which underlies the juxtaposed multiplepixel electrodes PX, at positions which correspond to every fourth oneof the pixel electrodes PX.

[0067] In addition, in this embodiment, the central axis of every fourthone of the pixel electrodes PX agrees with that of the corresponding oneof the holes CTH formed in the counter electrode CT, and each of theholes CTH is formed to have a width larger than the corresponding one ofthe pixel electrodes PX.

[0068]FIG. 5 is a cross-sectional view (which corresponds to thecross-sectional view of FIG. 2) showing the positional relationshipbetween the pixel electrodes PX and the holes CTH formed in the counterelectrode CT.

[0069] As can be seen from FIG. 5, each of the counter electrodes CTwhich are separated by the formation of the holes CTH (but are connectedfor electrical connection at their opposite peripheral ends) is formedto be superposed on pixel electrodes PX(2) adjacent to a pixel electrodePX(1) which is one of the pixel electrodes PX, and to be extended to thearea between each of the pixel electrodes PX(2) and the pixel electrodePX(1) as viewed in the direction of juxtaposition of the pixelelectrodes PX. Thus, each of the counter electrodes CT is formed to havean area superposed on the pixel electrode PX(l) and widths W.

[0070] The widths W are mainly determined from the point of view ofdecreasing an electric field other than an electric field whichcontributes to the control of the optical transmissivity of the liquidcrystal between the pixel electrode PX and the counter electrode CT,that is to say, an electric field which has a component perpendicular tothe substrate between the counter electrode CT and the pixel electrodePX. Accordingly, it is appropriate to make each of the widths W smallerthan the separation distance between the pixel electrode PX(l) and eachof the pixel electrodes PX(2) adjacent to the pixel electrode PX(1).

[0071] The widths W are preferably as wide as possible, but slightlysmaller than the respective separation distances.

[0072] In other words, the peripheral outline portion of the counterelectrode CT has only to lie at the intermediate position between thepixel electrode PX(1) and each of the pixel electrodes PX(2) adjacent tothe pixel electrode PX(1), and the counter electrode CT has to be widerthan the pixel electrode PX(1), preferably slightly wider.

[0073] The reason for this is that the existence of the widths W makesit possible to strengthen an electric field having a componentapproximately parallel to the transparent substrate in each pixel areaand to decrease an electric field which occurs in a directionperpendicular to the substrate and adversely affects the phenomenon ofimage retention. In addition, as the widths W are made larger, theabsorption loss of light due to transparent electrodes becomes smallerand higher optical transmissivity can be obtained.

[0074] The bottom-end same-material layer of each of the pixelelectrodes PX which are formed in this manner is connected to a contactportion of the source electrode SD1 of the thin film transistor TFTthrough a contact hole formed in the protective film PSV. The top-endsame-material layer is formed to be superposed on the counter voltagesignal line CL.

[0075] In the case of this construction, a capacitance element Cstgwhich uses as a dielectric film a stacked film made of the insulatingfilm GI and the protective film PSV is formed in the portion ofsuperposition of the counter electrode CT and each of the pixelelectrodes PX.

[0076] This capacitance element Cstg is formed for purposes such asstoring a video signal in the pixel electrode PX for a comparativelylong period even if the thin film transistor TFT is turned off after thevideo signal from the drain signal line DL is applied to the pixelelectrode PX via the thin film transistor TFT.

[0077] An alignment film ORI1 which covers the pixel electrodes PX isformed over the surface of the transparent substrate SUB 1 over whichthe pixel electrodes PX are formed in the above-described manner. Thisalignment film ORI1 is a film which is in direct contact with the liquidcrystal LC and determines the initial alignment direction of the liquidcrystal LC.

[0078] Incidentally, in Embodiment 1, the initial alignment direction ismade 75°with respect to the direction of application of an electricfield. The initial alignment direction is not limited to 75°, and may begreater than 0°and less than 90°, preferably 10°to 80°so that high-speedresponses (drivable at low voltages) can be achieved.

[0079] In the above-described embodiment, the gate signal lines GL, thecounter voltage signal lines CL and the drain signal lines DL are formedof chromium (Cr). However, it goes without saying that another highmelting point metal such as Mo, W, Ti or Ta or an alloy of two or morekinds of such metals or a stacked film made of two or more kinds of suchmetals may also be used.

[0080] Moreover, although in the above description the transparentconductive film is made of ITO, it goes without saying that similaradvantages can be obtained even with IZO (Indium-Zinc-Oxide).

[0081] The transparent substrate constructed in this manner is called aTFT substrate, and a transparent substrate disposed in opposition tothis TFT substrate with the liquid crystal LC interposed therebetween iscalled a filter substrate.

[0082] <<Filter Substrate>>

[0083] As shown in FIG. 2, on the liquid crystal-side surface of thefilter substrate, a black matrix BM is formed to separate the pixelareas from one another, and a filter FIL is formed to cover eachaperture of the black matrix BM that determines a substantial pixelarea.

[0084] An overcoat layer OC made of, for example, a resin layer isformed to cover the black matrix BM and the filter FIL, and an alignmentlayer ORI2 is formed on the overcoat layer OC.

[0085] The alignment direction of the alignment layer ORI2 is selectedto be the same as that of the alignment film ORI1 when the alignmentfilm ORI1 is superposed on the alignment layer ORI1. That is to say, thealignment of the molecules of the liquid crystal LC is made homogeneous.

[0086] <<Liquid Crystal Layer>>

[0087] In Embodiment 1, a liquid crystal having a dielectric anisotropyΔε of, for example, −5 is used, whereby it is possible to obtain a highoptical transmissivity. This is because the directors of the liquidcrystal molecules of a liquid crystal of negative Δε do not greatlychange due to an electric-field component perpendicular to a substratesurface.

[0088] Embodiment 1 uses a liquid crystal of negative Δε, but even if aliquid crystal of positive Δε is used, the effects and advantages of thepresent invention can similarly be obtained.

[0089] Since the liquid crystal of positive Δε is large in Δε and low inviscosity compared to the liquid crystal of negative Δε, the liquidcrystal of positive Δε has the advantage of being drivable at lowervoltages and at higher response speeds.

[0090] <<Entire Construction of Liquid Crystal Display Panel>>

[0091]FIG. 6 is a view of the entire construction of the liquid crystaldisplay panel, showing a display area AR constructed of an assembly ofpixel areas arranged in matrix form.

[0092] A transparent substrate SUB2 is formed to be slightly smallerthan the transparent substrate SUB1, and the right and bottom sides (asviewed in FIG. 6) of the transparent substrate SUB2 are disposed to beapproximately in flush with the corresponding sides of the transparentsubstrate SUB1.

[0093] Accordingly, areas which are not covered with the transparentsubstrate SUB2 are respectively formed along the left and top sides (asviewed in FIG. 5) of the transparent substrate SUB1, and gate signalterminals Tg and drain signal terminals Td are formed in the respectareas. The gate signal terminals Tg are formed for supplying scanningsignals to the respective gate signal lines GL, while the drain signalterminals Td are formed for supplying video signals to the respectivedrain signal lines DL.

[0094] The transparent substrate SUB2 is secured to the transparentsubstrate SUB1 by a sealing material SL formed along the periphery ofthe transparent substrate SUB2, and this sealing material SL also hasthe function of a sealing material for sealing the liquid crystal LCbetween the transparent substrates SUB1 and SUB2.

[0095] A liquid crystal filling port INJ is disposed in a portion of thesealing material SL, and after the gap between the transparentsubstrates SUB1 and SUB2 has been filled with the liquid crystal LCthrough the liquid crystal filling port INJ, the liquid crystal fillingport INJ is sealed by a liquid crystal sealing material (not shown).

[0096] Polarizers are respectively stuck to the outside surfaces of thetransparent substrates SUB1 and SUB2 in such a manner that thetransparent substrates SUB1 and SUB2 are interposed between thepolarizers.

[0097] <<Equivalent Circuit>>

[0098]FIG. 7 is a view showing the equivalent circuit of the liquidcrystal panel as well as the external circuits of the liquid crystalpanel.

[0099] Scanning signals (voltage signals) are sequentially supplied tothe individual gate signal lines GL disposed to be extended in thex-direction of FIG. 7 and to be juxtaposed in the y-direction of FIG. 7,by a vertical scanning circuit V.

[0100] The thin film transistors TFT in the respective pixel areasarranged along the one of the gate signal lines GL to which a scanningsignal is supplied are turned on by the scanning signal.

[0101] At this timing, video signals are supplied to the individualdrain signal lines DL from a video signal driver circuit H, and thesevideo signals are applied to the respective pixel electrodes PX via thethin film transistors of the corresponding pixel areas.

[0102] In the respective pixel areas, counter voltages are applied tothe counter electrodes CT formed together with the pixel electrodes PXvia the counter voltage signal lines CL, so that electric fields can begenerated between the pixel electrodes and the counter electrodes CT.

[0103] The optical transmissivity of the liquid crystal LC is controlledby the ones (in-plane electric fields) of these electric fields each ofwhich has a component parallel to the transparent substrate SUB1.

[0104] Incidentally, in FIG. 7, the symbols R, G and B shown in theindividual pixel areas represent that a red filter, a green filter and ablue filter are formed in the respective pixel areas.

[0105] <<Other Embodiments>>

[0106] In the above-described embodiment, the counter electrodes CT areformed below the pixel electrodes PX with the insulating film GIinterposed therebetween. However, the present invention is not limitedto this construction, and it goes without saying that the pixelelectrodes PX are formed below the counter electrodes CT with theinsulating film GI interposed therebetween.

[0107] In the above-described embodiment, the pixel electrodes PX formedin juxtaposition are formed as rectilinear strip-shaped electrodes inthe respective pixel areas.

[0108] However, the present invention is not limited to thisconstruction, and it goes without saying that each of the pixelelectrodes PX may be an element having one or more bent portions in thedirection of extension of the pixel electrode PX.

[0109] Such an electrode is called a multi domain scheme in which thedirection of an electric field generated between the electrode and thecounter electrode CT is made different to provide the advantage ofcanceling a difference in the optical transmissivity of a liquid crystalwhen a display area is viewed in any direction different from thedirection normal to its front surface.

[0110] Even in this case, the holes CTH can be formed in the counterelectrode CT at locations corresponding to the bent extended portion ofthe pixel electrode PX.

[0111]FIG. 9 is a plan view which corresponds to FIG. 1, showing anexample to which the multi domain scheme is applied.

[0112] Each of the pixel electrodes PX has, for example, a zigzagpattern along its extension direction, and the holes CTH each having azigzag shape along the zigzag pattern are respectively formed in thecounter electrodes CT which are superposed on some of the pixelelectrodes PX (for example, every other one of the pixel electrodes PX).

[0113] The extension direction of the pixel electrodes PX is along they-direction of FIG. 9, but the present invention is not limited to thisconstruction and can, of course, be applied to a construction in whichthe extension direction of the pixel electrodes PX is along thex-direction of FIG. 9.

[0114] In the above-described embodiment, an electrode which is formedover nearly the whole of the central portion of the pixel area exceptthe periphery thereof serves as the counter electrode CT, while pluralstrip-shaped electrodes which are juxtaposed in one direction serve asthe pixel electrodes PX. However, an electrode which is formed over thecentral portion of the pixel area except the periphery thereof may beused as the pixel electrode PX, while plural strip-shaped electrodeswhich are juxtaposed in one direction may be used as the counterelectrode CT.

[0115] As is apparent from the foregoing description, in accordance withthe liquid crystal display device according to the present invention, itis possible to prevent the occurrence of horizontal smear and imageretention.

What is claimed is:
 1. A liquid crystal display device comprising: afirst substrate; a second substrate facing the first substrate, a liquidcrystal layer interposed between the first and second substrates; atleast one pixel area being defined by a plurality of gate lines and aplurality of drain lines arranged in a matrix over the first substrate,wherein the plurality of gate lines are extending in a first direction,and the plurality of drain lines are extending in a second direction; afirst electrode assigned to the pixel area, the first electrode providedover the first substrate; a second electrode assigned to the pixel areaand facing the first electrode, the second electrode provided over thefirst substrate and being transparent, the second electrode having asolid portion and a hollow portion, the hollow portion being superposedto at least a portion of the first electrode; and an insulating layerprovided between the first and second electrodes.
 2. The liquid crystaldisplay device according to claim 1 , wherein the hollow portion of thesecond electrode has a width extending in the first direction and alength extending in the second direction, the length being substantiallygreater than the width.
 3. The liquid crystal display device accordingto claim 1 wherein the first electrode having a comb shape structureincluding a plurality of branch portions extending in the seconddirection and a connecting portion connected to the branch portions andextending in the first direction, wherein one or more of the pluralityof branch portions being superposed to the solid portion of the secondelectrode, and one or more of the plurality of branch portions beingsuperposed to the hollow portion of the second electrode.
 4. The liquidcrystal display device according to claim 3 , wherein the secondelectrode has a plurality of hollow portions, the display device furtherincluding: an outline of the second direction of at least one hollowportion being disposed between said plurality of branch portions.
 5. Theliquid crystal display device according to claim 4 further including: awidth of each branch portion in the first direction being smaller than awidth of the hollow portion in the first direction.
 6. The liquidcrystal display device according to claim 4 wherein the first electrodeis a pixel electrode, and the second electrode is a counter electrode.7. The liquid crystal display device according to claim 6 furtherincluding: a switching element being assigned to the pixel area, whereinone of the plurality of gate lines is applying a scan signal to theswitching element, one of the plurality of drain lines is applying avideo signal to the pixel electrode via the switching element.
 8. Theliquid crystal display device according to claim 7 wherein the liquidcrystal layer is one selected from the following group: a materialhaving a positive dielectric anisotropy AE and a material having anegative dielectric anisotropy Δε.
 9. The liquid crystal display deviceaccording to claim 8 , wherein an alignment of molecules of the liquidcrystal layer is homogeneous.
 10. The liquid crystal display deviceaccording to claim 8 wherein one of the plurality of branch portions hasa zigzag pattern structure.
 11. The liquid crystal display deviceaccording to claim 6 , wherein the counter electrode is provided overthe pixel electrode.
 12. The liquid crystal display device according toclaim 11 wherein the counter electrode is one selected from thefollowing group: ITO, IZO and IGO.
 13. The liquid crystal display deviceaccording to claim 12 further including: a plurality of counter voltagelines disposed between two gate lines and applying a voltage to thecounter electrode.
 11. 14. The liquid crystal display device accordingto claim 6 , wherein the pixel electrode is provided over the counterelectrode.
 15. The liquid crystal display device according to claim 14wherein the counter electrode is one selected from the following group:ITO, IZO and IGO.
 16. The liquid crystal display device according toclaim 15 further including: a plurality of counter voltage linesdisposed between two gate lines and applying a voltage to the counterelectrode.
 17. A liquid crystal display device comprising: a firstsubstrate a second substrate facing the first substrate; a liquidcrystal layer interposed between the first and second substrates; acounter electrode having a hole and formed over the first substrate; apixel electrode formed over the first substrate, the pixel electrodehaving a plurality of branch portions and a connection portionconnecting the branch portions, each branch portion being separated froman adjacent branch portion by a first distance; and an insulating layerinterposed between the counter electrode and the pixel electrode,wherein one of the branch portions of the pixel electrode is overlappingthe counter electrode and another of the branch portions of the pixelelectrode is overlapping to the hole of the counter electrode, the holehaving a first width in a first direction and the branch portionoverlapping to the hole having a second width in the first direction,wherein a second distance defines an amount of distance by which an edgeof hole extends beyond an edge of the branch portion overlapping to thehole, and wherein the first distance is greater than the seconddistance.
 18. The liquid crystal display device according to claim 17wherein the second distance is greater than the second width of thebranch portion.
 19. The liquid crystal display device according to claim17 wherein the first width of the hole is greater than the second widthof the branch portion vertically aligned to the hole.
 20. The liquidcrystal display device according to claim 17 wherein at least two branchportions of the pixel electrode are overlapping the counter electrode.21. The liquid crystal display device according to claim 17 wherein thehole of the counter electrode forms a slit shape.